Novolac-epoxy resin foam, foamable composition for making novolac-epoxy resin foam and method of making novolac-epoxy resin foam

ABSTRACT

Provided is a foamable composition adapted to form a cross-linked novolac-epoxy resin foam. The foamable composition is formulated from a composition comprising at least one novolac resin, at least one epoxy resin, and at least one blowing agent.

This is a divisional of U.S. Ser. No. 10/265,389, filed Oct. 7, 2002,now U.S. Pat. No. 6,610,754, which is a divisional of U.S. Ser. No.09/436,971, filed Nov. 9, 1999, now U.S. Pat. No. 6,492,432, thecomplete disclosures of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a novolac-epoxy resin foam, a methodfor making a novolac-epoxy resin foam, and a foamable composition forforming a novolac-epoxy resin foam.

BACKGROUND OF THE INVENTION

Phenolic resin foams are well known and provide many advantages overpolyurethane foams. For example, polyurethane foams produce many toxicfumes when burned, whereas phenolic foams produce significantly lesstoxic fumes when burned. Phenolic resin foams are usually formed from aresol resin, as described in my U.S. Pat. Nos. 5,616,626 and 5,693,684,the complete disclosures of which are incorporated herein by reference.Resol resins are formed by reacting phenol based compounds with analdehyde. Linear resol resins are commonly known as novolac resins.

Polyurethane foams can be easily be formed having a closed-cellstructure. A closed-cell structure is understood as the ability of thecell wall to inhibit the outward diffusion of trapped blowing gas andthe inward diffusion of air. Such closed-cell polyurethane foams can beproduced under atmospheric pressure. In contrast, conventional phenolicresin foams must be produced under high pressure to form such aclosed-cell structure. U.S. Pat. No. 4,423,163 describes such a highpressure method for making a closed-cell phenolic resin foam, in whichthe foam is produced under about 6 psi. The requirement of pressure formaking a closed-cell phenolic foam results in significant disadvantagesand is not commercially feasible, especially when compared toclosed-cell polyurethane foams that can be produced under atmosphericpressure.

My U.S. patent application Ser. No. 09/070,765, the complete disclosureof which is incorporated herein by reference, discloses a method forforming closed-cell phenolic resin foam, which utilizes a bond strengthenhancing agent so that the foam can be formed under ambient pressures.

There is a need for other methods of making closed-cell phenolic resinfoams that do not require the use of pressure greater than atmospheric.There is also a need for an adjustable, phenolic based foam system whichcan be adapted to be sprayable, to provide various levels of closed andopen cells, to provide different levels of flexibility, and to meetlocal residential and commercial building flamability codes.

Spray foaming is a process in which two or more reactive components aremixed, such as in a mixing head, where they begin to react. Theresulting reaction mixture is then sprayed onto a surface where themixture foams and cures, thereby forming a cured foam layer on thesurface. A mixing head suitable for use in carrying out spray foaming isdescribed in U.S. Pat. No. 4,332,335, which is incorporated herein byreference. The head consists of a mixing chamber which communicates witha discharge orifice and first and second ducts which dispense thereactive components into the mixing chamber. Means are provided forregulating the flow of the reactants to the reaction chamber.

To be suitable for spraying, the foam-forming composition must have alow viscosity. For spraying on vertical surfaces the foam-formingcomposition must also have a fast cure speed to prevent gravity-inducedsagging or running of the foam. Therefore, spraying methods have beenused primarily for foam-forming compositions consisting of polyurethaneand polyisocyanate resins, which have the combination of a low viscosityand a fast cure rate. However, foam-forming compositions based onpolyurethane and polyisocyanate produce a polyurethane foam having anundesirably low temperature resistance, which significantly limits theuse of polyurethane foams. For example, insulation for use inresidential homes, commercial buildings, foundries, automobiles, boats,and wherever high temperature insulation is required, must have atemperature resistance significantly greater than that of polyurethanefoams. The temperature resistance of the polyurethane foam can beincreased slightly by using additives. However, such additives have manyundesirable effects on the properties of the foam. Furthermore, whenpolyurethane foams are burned they undesirably produce fumes which arevery toxic to humans.

Foams made from phenolic resins have a temperature resistancesignificantly greater than polyurethane foams. Furthermore, foams madefrom phenolic resins do not produce toxic fumes when burned. However,known foam-forming, phenolic resin compositions have not previously beenused in spraying methods because they exhibit undesirably slow curingrates, the viscosity of the phenolic resin composition is undesirablyhigh for spray applications, and chemical blowing agents must be addedto produce the foam. Use of chemical blowing agents, such aschlorofluorocarbons, are undesirable because they are environmentallyunfriendly. Thus, there is and has been a need for a sprayable,foam-forming composition having the combination of properties of (a) notrequiring the use of an external blowing agent, (b) having a viscositysuitable for spraying, (c) having a suitably fast curing rate, and (d)when suitably cured providing a foam having a high temperatureresistance and which does not produce toxic fumes when burned.

My U.S. Pat. No. 5,693,684 discloses a sprayable, foam-forming phenolicresin composition. Resol resins are utilized, preferably in combinationwith a phenol compound. This patent does not specifically disclose theuse of epoxy resins in combination with novolac resins.

U.S. Pat. No. 4,291,146 discloses a heat-curable mixture of epoxideresins and beta-aminocrotonic acid derivatives. This patent disclosesthat the epoxy formulations may be used to form foams. Use of aglycidylised phenol novolac resin having epoxide equivalent weight of175 is disclosed in the examples. However, this patent does not disclosereacting an epoxy resin with hydroxyl groups present on a novolac resinwhile blowing to form a foam, nor a flexible system of providingdifferent levels of flexibility in the cured foam by adjusting the ratioof epoxy resin to novolac resin. This patent also does not disclose afoam that is suitable for spraying.

There is a need for an adjustable, foam-forming system to providevarying levels of foam flexibility, a neutral pH to avoid corrosion, andwhich can be adapted to be sprayable. There is also a need for aflame-retardant foam which does not produce toxic fumes when burned.

SUMMARY OF THE INVENTION

The above objectives and other objectives are achieved by the novelcombination of a novlac resin and an epoxy resin to provide foams. Theflexibility of the foam can be easily increased by increasing the amountof novolac resin compared to the amount of epoxy resin. The foam formingcomposition can easily be adapted for spraying applications.

The present invention provides a novel foamable composition adapted toform a cross-linked novolac-epoxy resin foam. The foamable compositionis formulated from a composition comprising at least one novolac resin,at least one epoxy resin, and at least one blowing agent.

The present invention also provides a flame-retardant, foamable,novolac-epoxy resin composition. The foamable composition is formulatedfrom a composition comprising at least one novolac resin, at least oneepoxy resin, at least one blowing agent and at least one flameretardant.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates is graph of the results of multiple compressions on anovolac-epoxy resin according to the present invention;

FIG. 2 illustrates a graph of the results of compressive strengthparallel to rise on a novolac-epoxy resin according to the presentinvention; and

FIG. 3 illustrates a graph of the results of compressive strengthperpendicular to rise on a novolac-epoxy resin according to the presentinvention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The reaction mechanism between novolac resin and epoxy is now wellknown. Novolac resin is commonly used to cure epoxy resins. However,novolac/epoxy resin combinations have not been used to make foams sincethe cure rate and reactivity were too low. However, by using the newcombinations of specific epoxy and novolac resins described herein, thereactivity is greatly enhanced and suitable for any foaming application.Furthermore, it has now been found that the combination of novolac andepoxy resin, where the novolac is used in far greater amounts thanmerely as a curing agent, provides many unexpected advantages asfollows.

The present invention relates to a highly adjustable, foam-formingsystem based on the combination of novolac resin and epoxy resin toprovide a broad range of desired foam properties. By varying the ratioof novolac resin to epoxy resin, the flexibility of the cured foam canbe altered dramatically. In general, greater amounts of novolac resinprovide a more flexible foam and greater amounts of epoxy resin providea more rigid foam. Based on the disclosure provided herein, one ofordinary skill in the art of formulating foamable compositions willeasily be able to provide the desired level of flexibility in the finalcured foam by adjusting the ratio of novolac resin to epoxy resin. Forexample, a flexibility similar to a rubber tire in which a 1 inch foamcan be bent 180° is easily attainable, as well as very rigid foamshaving a high tensile strength.

The combination of novolac resin and epoxy resin also provides theunexpected capability of providing foams having a high closed-cellcontent of about 80 to greater than 90%, with curing under ambientpressures. Usually, high pressures are required to form close-cellphenolic resin foams. High insulation R values of about 6.5 areattainable for 1 inch closed-cell novolac-epoxy resin foam. Closed-cellcontents of at least 80%, preferably at least 90% are easily attainable.However, if desired, the foamable composition can be formulated toprovide an open cell foam for the desired application, for example, bythe use of well-known lysing agents such as sodium laureth sulfate ordodecyl benzene sulfonic acid.

The novolac-epoxy resin foams produced according to the presentinvention provide the advantage that when burned they do not producesignificant amounts of toxic fumes, rather only carbon dioxide, carbonand few nitrous oxides. In contrast, other conventional foams such aspolyurethanes produce cyanide when burned. If desired, the flamabilitycan be reduced to levels which meet industrial and residential firecodes, as described below.

The foamable composition can be formulated to have any desired pH.Preferably, the foamable composition is formulated to have a pH of fromabout 7 to about 9, and more preferably about 7, which is non-corrosive.Most preferably, the foamable composition is substantially acid free. Inthis manner, the cured foam will be non-acidic and non-corrosive. Acidicfoams cause many problems such as corroding the surrounding materialsand machinery used to form and shape the foam.

The flexible foamable composition can be easily formulated for anydesired application. For example, liquid novolac resins and epoxy resinscan be utilized to form sprayable, foamable compositions, to providefoams having any desired level of flexibility. Alternatively, solidand/or high viscosity novolac resins and epoxy resins can be dissolvedin a solvent blowing agent to form sprayable, foamable compositions. Fornon-spray foaming applications, the sprayable formulations may be usedif desired, or highly viscous foamable compositions can be formulated.

The novolac-epoxy resin foams produced according to the presentinvention are suitable for almost any foaming application, since theyare capable of high degrees of flexibility or rigidity, temperatureresistance, chemical resistance, and reduced toxicity when burned.Furthermore, the foams can be produced by many methods, includingspray-foaming, and can be formulated to provide little outgassing foruse in confined spaces, as well as open or closed-cells. The followingare non-limiting examples of suitable applications:

Mining applications where non-toxicity, high temperature resistance, andlow outgassing are required since the foam is sprayed in a closed space;

Automotive applications where many different types of foam propertiesare required, such as high temperature resistance for heat and noiseshielding from the engine, as well as insulation from outsidetemperature and noise, light weight and non-toxicity are also required;

Residential and commercial building applications, can be formulated tobe non-flammable such that the foam is self extinguishing and does notproduce toxic fumes, rigid for use in support panels, such as shown inU.S. Pat. No. 4,423,163, or can be sprayable for application in roofs,side walls, floors or any space;

Aircraft applications, can be formulated to provide flexible or highstrength rigid foams, major factors include light weight, non-toxic whenburned, high temperature resistance, corrosion resistance, and highinsulation properties;

Military ships, which require foams that can be used as flooring panels,fuse boxes, missile silos, and the like, where high temperatureresistance, corrosion protection, and low toxicity when burned are majorfactors;

Prototyping applications, for example industrial design engineers wherecorrosion and flamability are major factors since acidic foams cancorrode knifes and surrounding materials, such as decals, paints, etc.,compositions can be formulated to provide rigid yet easily cuttable andlight weight foams;

Artistic applications such as sculptures and movie or play sets, wherecorrosion and flamability are major factors, acidic foams can corrodeknifes and surrounding materials, such as decals, paints, etc., foam canbe formed to be rigid yet easily cuttable and light weight;

Aerospace applications, which require high temperature resistance andflexibility over a wide temperature range to avoid delamination fromcryogenic tanks and other equipment that expands and contracts, also asablative material during reentry into atmosphere;

Heat shielding applications, such as on oil rigs, petroleum storagefacilities, combustion chambers, power plants, and the like, where hightemperature resistance and low toxicity are required;

Mass-transit applications, such as busses and trains, where lightweight, non-toxicity, and high temperature resistance are required; and

Insulation applications, such as flexible tapes, rigid panels, flexiblepanels, boards and laminates.

As can be appreciated from the above, the uses for the non-toxic,non-corrosive, high temperature resistant foams according to the presentinvention which can be easily tailored to provide different levels offlexibility has limitless applications.

The present invention will now be described with reference to differentembodiments, without being limited thereto.

Sprayable, Foamable Composition

Sprayable, foamable compositions usually require a low viscosity, in therange of about 50 to about 1000 centipoise at 25° C., preferably about50 to about 500 centipoise at 25° C. For most spraying applications,which are on non-horizontal surfaces or ceilings where gravity-inducedsagging or running can be a problem, the foamable composition must alsohave a fast cure speed, on the order of about 5 minutes or less,preferably about 1 minute or less. Cure speed is the time from when thenovolac and epoxy resins are mixed to when a tack free surface is formedon the foam. When a tack free surface is formed on the foam, the foamusually has sufficient integrity to substantially avoid sagging orrunning. The curing rate for completely curing the novolac-epoxy foamcan be significantly longer, on the order of about 1 hour.

Surprisingly, the foamable compositions according to the presentinvention can be formulated to provide a fast cure speed and lowviscosity which are suitable for spraying. In this regard, the novolacresin selected should be liquid and have a viscosity of from about 100to about 3,000 centipoise at 25° C., and more preferably about 500 toabout 750 centipoise at 25° C. If a mixture of novolac resins areutilized, the combined viscosity should be within these ranges. Thenovolac resin should also have a number average molecular weight that issuitable for the desired foaming application. For example, when usingnovolac resins formulated from phenol, suitable number average molecularweights are from about 100 to about 500, preferably about 100 to 400,and most preferably from about 150 to about 250. Preferably, the novolacresin is free of epoxide groups.

There are many commercially available novolac resins that are suitablefor use in formulating the foamable composition. Examples include, butare not limited to HRJ444, HRJ-1166, HRJ-406, HRJ-425, and SP-1068 fromS.I.I.

If desired, the novolac resin can be easily formulated from a phenolbased compound and an aldehyde. The formation of novolac resins is nowwell known and one skilled in the art will easily be able to form thedesired novolac resin. For example, 1 molar ratio of phenol to aldehydecan be reacted un the presence of well known acid catalysts until thedesired molecular weight is obtained, and then neutralize by adding wellknown bases. Novolac resin is a substantially linear chain ofphenol-based groups bound together. The novolac resin is usually quitestable and does not require refrigeration. For some applications, minoramounts of non-linear Resol resin may be present.

The novolac resin can be used in any desired amount. In general, thegreater the amount of novolac resin, the more flexible the curednovolac-epoxy resin foam. Suitable amounts for the novolac resin arefrom about 5 to about 95% by weight, preferably about 20 to about 80% byweight, and more preferably from about 40 to about 60% by weight. Allweight % are based on the total weight of the foamable compositionunless stated otherwise.

For sprayable applications, the epoxy resin should also be a liquidunder ambient conditions. Suitable viscosities for the epoxy resin arefrom about 100 to about 10,000 centipoise at 25° C., preferably about1,000 to about 6,000 centipoise at 25° C. The epoxy resin preferably hasa number average molecular weight of from about 250 to about 650.

The epoxy resin can be used any amount desired. In general, the greaterthe amount of epoxy resin, the more rigid the cured novolac-epoxy resinfoam. Suitable amounts for the epoxy resin are from about 5 to about 95%by weight, preferably about 20 to about 80% by weight, more preferablyfrom about 40 to about 60% by weight.

Preferably, the epoxy resin has about 2 or more terminal epoxide groupson average to provide a fast cure speed. For spray-foam applications,the cure time should be about 5 min or less, preferably 1 min or less.To provide such fast cure speeds, the epoxy resin or resins selectedshould have about 2 or more terminal epoxide groups on average,preferably about 2 to about 5, and most preferably about 3 on average.An average of 3 terminal epoxy groups is capable of providing a curespeed of about 45 seconds to 1 minute. However, in applications where afast cure speed is not required, less reactive epoxy resins can be used,such as when spraying on a horizontal surface where sagging or runningis not a problem. Epoxy resins having less than 2 terminal epoxy groupson average generally require about 1 hour to cure. A slower curingfoamable composition may be desired where multiple layers are applied,such that later layers can be applied before the lower layers are cured.In this manner, the layers can co-cure to provide enhanced adhesiontherebetween.

One or ordinary skill in the art will be able to formulate any desiredepoxy resin can by now well known techniques. Examples of suitablecommercially available epoxy resins includes Epon Resin 8161, 826 and828 (Shell Chemical) and PC-601 and PC-661 (Polycast Chemical).

Any suitable blowing agent can be utilized. The blowing agent can beformulated from any inorganic and/or organic substance that provides thedesired vapor pressure at the selected blowing temperature, such as byvolatization and/or chemical reaction. Preferably, a reactive blowingagent is utilized which produces a gas by an in situ reaction during theblowing and curing stages of forming the novolac-epoxy foam. An exampleof a preferred reactive blowing agent is one which contains a reactivehydrogen group, such that when an amine catalyst is utilized, thereactive hydrogen group reacts with the amine to form hydrogen gas andblow the foam. The chemical reaction between the reactive hydrogen groupand the amine group also provides heat which increases the cure speed ofthe novolac-epoxy resin mixture. When the novolac and epoxy resins areinitially mixed at ambient temperatures, they generally do not produce asignificant amount of initial heat of reaction and the reaction usuallyproceeds slowly. However, when a reactive blowing agent is utilized,temperature increases from room temperature to a temperature in therange of about 100 to 140° F. within 1 minute after mixing the novolacand epoxy resins are attainable, which includes heat generated by thereaction of the reactive blowing agent to form a blowing gas. Afterabout 20 minutes, the temperature usually increases to about 300° F.upon which the reaction is about 98% complete.

Specific examples of reactive blowing agents include the commerciallyavailable EF-10 (Applied Polaramics) and Z-6040, Z-6030 and Z-6011 (DowCorning), which are all silicone compounds having a reactive hydrogengroup (hydrogen donor group) which is capable of reacting with an aminefunctional group. Preferably, the reactive blowing agent comprisessilicone having a reactive hydrogen group that is capable of reactingwith an amine group under the desired blowing conditions. Siliconecompounds are only an example of reactive blowing agents, and thoseskilled in the art are well aware of many other types of reactiveblowing agents which produce a blowing gas upon reaction during blowingof the foam, which are suitable for use in the present invention.

While not desired from the standpoint of environmental friendliness, theblowing agent can be formulated from one or more volatile organicliquids that provide the desired vapor pressure at the selected blowingtemperature. Examples of suitable liquid organic blowing agents includehydrocarbons and halogenated hydrocarbons, such as chlorofluorocarbons,fluorocarbons, ethanated chlorofluorocarbons and chlorocarbons.

If desired, water can be utilized as a blowing agent, especially whenhigher density foams are required Novolac resins are typically suspendedin an aqueous solution, which can be used as the blowing agent. Typicalamounts of water are from about 1% to about 10% water, based on theweight of the novolac resin.

In spray-foam applications, preferably a reactive blowing agent isutilized which generates a blowing gas by reaction during curing of thenovolac and epoxy resins and which provides heat of reaction tofacilitate a fast cure speed. A particularly preferred reactive blowingagent is one that contains a reactive hydrogen group that reacts with anamine group present in an amine catalyst.

Blowing agents are now well known in the art. One skilled in the art offormulation foamable compositions will be able to select desired blowingagents as required for the particular application. For example, forin-plant applications where heat can easily be applied to the foamablecomposition, liquid solvent blowing agents may be desired. However, forout-in-the-field applications, such as in construction or miningapplications, where application of heat may be difficult, a reactiveblowing agent can be utilized which provides heat during the formationof the blowing gas to increase the cure speed of the novolac and epoxyresins. Usually, a reactive blowing agent is required for spray foamingapplications to provide a suitable cure speed to avoid sagging orrunning of the foam.

If desired, higher viscosity and/or solid novolac and epoxy resins canbe utilized, if they are adequately dissolved in a solvent to provide asolutions suitable for spraying. The solvent may also be the blowingagent. However, the preferred method is the use of low viscosity novolacresins and liquid epoxy resins, as described above.

The use of catalysts is not required for all applications. However, afree-radical generating catalyst is preferably included to facilitatering-opening of the epoxide groups and further enhance the cure speed.Any conventional epoxide catalyst can be used. However, low pH catalystsmay undesirably hinder curing of the novolac resin, which is usuallycured using a base, such as an amine or hydroxide group. Preferably, abasic catalyst is incorporated to increase curing of the novolac resin.

Preferably, a dual function catalyst added which provides catalyticproperties as well as reacting with a reactive blowing agent to generatea blowing gas. For example, an amine catalyst can be combined with areactive blowing agent having a reactive hydrogen group. In this mannerthe amine catalyzes the curing of the novolac and epoxy resins as wellas reacts with the reactive hydrogen group to form hydrogen gas and blowthe foamable composition. This reaction also has the added benefit ofsupplying heat to increase the cure speed. Examples of suitable dualfunction catalysts include alkyl polyamine, triethyl amine, aliphaticamines and polyaminoamides.

A surfactant can be added to facilitate the production of a foam bunhaving a good height, small, uniform cells, and a low thermalconductivity. Surfactants can also be added to reduce the shearnecessary to form a homogenous mixture of novolac resin and epoxy resin,for example, by creation of micelles. Furthermore, surfactants can beused to reduce the viscosity of the composition to about 1000 or less.

Examples of suitable surfactants include ethoxylates, which arecompounds containing recurring ether linkages and are made by reactingethylene oxide and/or higher alkylene oxides, such as propylene oxide,butylene oxide, styrene oxide, etc. with various compounds or initiatorscontaining an active hydrogen atom such as alcohols, alkylphenols, fattyacids, fatty acid amides, fatty acid esters, etc. These surfactantsinclude, but are not limited to, the following surfactant categories:alcohol ethoxylates; alkyphenol ethoxylates; polyoxyethylene esters;ethoxylated anhydrosorbitol esters; ethoxylated natural fats, oils andwaxes; ethoxylated lanolin; polyoxyethylene amines; polyoxyethylenefatty acid amides and block copolymers of ethylene oxide with higheralkylene oxides.

Polyoxyethylene esters include, but are not limited to, ethoxylated monoand diesters of fatty acids and aliphatic acids. These compounds includelaurates, oleates, stearates, pelargonates, tallates and rosin acidesters. These polyoxyethylene esters include polyoxyethylene esters soldunder the trademarks: EMEREST by Henkel; ETHOFAT made Akzo Nobel; KESSOmade by Stepan; and WITCONOL made by Witco.

Ethoxylated anhydrosorbitol mono, di and triesters include, but are notlimited to, oleates, laurates, palmitates, stearates, and tallates.These surfactants include surfactants sold under the reademarks: EMSORBmade by Henkel and SPAN and TWEEN made by ICI.

Ethoxylated castor oil and laolin are examples of ethoxylated naturalproducts. These ethoxylated natural products include thoxylated naturalproducts sold under trademarks: SURFACTOL made by CasCem; EMERY made byHenkel; and RITACHOL made by R.I.T.A.

Ethoxylated fatty acid amides are usually made by reacting one or moremoles of ethylene oxide with and amide made from diethonolamine that hasbeen esterifies with a fatty acid, such as lauric, hydrogenated tallowor oleic. These ethoxylated fatty acid amides include ethoxylated fattyacids sold under the trademarks: ETHOMID made by Akzo Nobel and AMIDOXmade by Stephan.

Block copolymers are formed when both ehtylene oxide and higher allyloxides, such as propylene oxide, are selectively reacted with a basecompound containing and active hydrogen. Base compounds or initiatorsinclude glycols, diamines, etc. These initiators include initiators soldunder the trademarks: ANTAROX made by Rhone-Poulenc and PLURONIC andTETRONIC made by BASF.

The above variations in the surfactants allow nonionic organicsurfactants to be made covering a wide rage of emulsification. Thesesurfactants contain both hydrophillic and lipophilic groups on the samemolecule. The emulsion characteristics of surfactants can be compared bydetermining their hydrophilic/lipophilic balance (HLB). HLB values rangefrom 1 to 30 with lipophilic surfactants at the low end of the range andhydrophilic surfactants at the high end of the range. The nonioic,organic surfactants utilized in the present invention to stabilize thefoam preferably are those which are highly hydrophilic. In particular,preferred nonionic, organic surfactants exhibit a hydrophilic/lipophilicbalance of at least about 12 and more preferably, at least about 15 orgreater.

A particularly preferred surfactant is the commercially available SF1188 (General Electric).

The amount of nonionic, organic surfactant utilized in the foamablecomposition typically ranges from about 0.01% to about 5% by weight, andpreferably, from about 0.1% to about 3% by weight.

If desired, the foamable composition can be easily formulated to reducethe flamability of the foam. When non-flamability is desired, the numberof hydroxyl groups in the foamable composition should be reduced,preferably the composition is free of hydroxyl groups. The presence ofhydroxyl groups generally increases the flamability of the foam.

To further reduce the flamability of the foam, a flame retardant can beincorporated in the foamable composition. Flame retardants are wellknown in the art and one skilled in the art will easily be able selectand utilize flame retardants in the foamable composition base on thedisclosure provided herein. Examples of suitable flame retardantsinclude silicates and brominated aluminum oxide. A commercial example isFyrol (DuPont). A preferred flame retardant is sodium silicate, whichreduces flamability by encapsulation. Once the silicate group is heatedin the presence of a flame, it forms an encapsulating glass and givesoff water, which prevents further burning of the foam. Thus, the foam isself-extinguishing. In this manner, the novolac-epoxy foam can beformulated to meet or exceed commercial and residential building codes.Sodium silicate can be added in an amount to provide the desired levelof non-flamability. Suitable amounts have been found to be from about0.001:1 to about 1:1 (moles flame retardant):(moles epoxy). Silicateflame retardants can be in amounts up to 40% by weight, preferably fromabout 10 to about 40% by weight.

Usually, the sprayable, foamable formulation is formulated in 2 or moreparts which are combined in the spray head during application. Usually,the novolac resin is separated from the epoxy resin since the resins canco-cure over time under ambient conditions. However, if stabilizing orblocking agents are added, it may be possible to have the novolac resinand epoxy resin in the same part. Surfactants can generally be addedwith either the novolac or epoxy resin. If using a reactive blowingagent, it should be added in the part containing the novolac resin andthe amine catalyst combined with the part containing the epoxy resin.One of ordinary skill in the art of formulating foam compositions willeasily be able to formulate two or more part formulations which canadded in the field forming the novolac-epoxy resin foam on demand.

Non-Spray Foaming

The viscosity of the foamable composition can be significantly higherfor non-spray foaming applications. Therefore, higher viscosities forthe novolac and epoxy resins can be tolerated. In some instances, solid,powdered novolac and/or epoxy resins can be utilized. Novolac resins caneven be partially or completely replaced with well-known non-linearResol resins. However, from the standpoint of long-term stability of theresins, linear novolac resins are preferred.

The present invention will further explained with reference to thefollowing non-limiting examples.

EXAMPLES

An Epoxy Resin A was first formed by combining the components shown inTable 1.

TABLE 1 Epoxy Resin A Component MW Amount (g) (1) Epichlorohydrin 92.532128.19 (2) Bisphenol A 228.28 2282.8 (3) Ca(OH)₂ 58

1 and 2 were added to a 5 liter reaction flask. Then the catalyst wastitrated in at a rate of 10 ml per min.

Time Temp. Procedure  8:45 am 20° C. Add 1 and 2 to vessel  9:50 am 20°C. Turn on stir 10:00 am 24° C. Add 3 powder; add slow 10:35 am 81° C.Catalyst is in solution 11:35 am 92° C. Resin viscosity 78 cp's 12:15 pm65° C. Resin viscosity 96 cp's  1:20 pm 50° C. Resin viscosity 150 cp's 2:10 pm 50° C. Resin viscosity 228 cp's  3:00 pm 40° C. Resin viscosity340 cp's  4:00 pm 27° C. Resin viscosity 1430 cp's  4:30 pm 27° C. Shutreaction down

The physical properties of the Epoxy Resin A were tested and the resultsare shown in Table 2.

TABLE 2 Reactivity pH Solids Viscosity 28 sec gel 8.5 68% 2600 cps

A Novolac Resin A was formed by combining the components shown in Table3.

TABLE 3 Novolac Resin A Component MW Weight (g) (1) C₆H₆O 94.11 1882.2 g(2) CH₂O 30.03 1201.2 g (3) H₂So₄ 57.69 g (4) NaOH 40.1 g

Components 1 and 3 were added to a 5 liter flask and the stirrer wasturned on. Component 2 was titrated into the flask at the rate of 30 mlper minute until completely consumed. The temperature was monitored andnot allowed to exceed 110° C. The mixture was cook at about 95° C. Afterabout 1 hour a sample of the novolac resin was removed and the viscositytested. The reaction was stopped when the viscosity reached 450centipoise at 95° C.

Start Time Temp. Procedure  8:17 am 20° C. Add 1 and 3  8:25 am 20° C.Mixing started  8:30 am 22° C. Start to titrate  8:55 sm 98° C.Titration finished  9:50 am 96° C. Viscosity 290 cp's @ 95° C. 10:45 am97° C. Viscosity 360 cp's @ 95° C. 12:00 99° C. Viscosity 430 cp's @ 95°C. 12:30 pm 95° C. Shut reaction down  1:00 pm 88° C. Neutralize withNaOH  1:01 pm 86° C. Add 40.1 g of 4 pH 8.5  1:10 pm 85° C. Add 5.2 g ofNAOH pH 8  1:30 pm 77° C. Shut reaction down

The physical properties the Novolac Resin were tested and the resultsare shown in Table 4.

TABLE 4 Viscosity Non Volatiles pH RI Reactivity 2200 @ 25° C. 72% 8.31.5115 35 sec gel time

The color was red-orange.

A second Epoxy Resin B was formed by combining the components shown inTable 5.

TABLE 5 Epoxy Resin B Component MW Weight (g) (1) Epichlorohydrin 92.53g 1943.1 g (2) Bisphenol A 228.28 g 2282.8 g (3) Ca(OH)₂ 56.4 g (4)Tetrabromo-o cresol 145.2 g

Components 1, 2 and 4 were added to a 7 liter reaction flask. 4 was cutinto solution. Heat was added as needed.

Time Temp. Procedure  9:15 am 20° C. Add 1, 2, 4 to reactor  9:30 am 25°C. ↑Δ to 50° C.; mix 10:15 am 50° C. Mix in Ca(OH)₂ 10:45 am 83° C.Refluxing; start to read viscosity 11:30 am 83° C. Viscosity 850 cp's12:30 pm 85° C. Viscosity 1240 cp's 12:50 pm 80° C. Viscosity 1400 cp's 1:30 pm 81° C. Viscosity 2001 cp's  1:35 pm 80° C. Shut reaction down 4:30 pm 25° C. Viscosity 3300 cp's

The physical properties of Epoxy Resin B were tested and the results areshown in Table 6.

TABLE 6 Solids pH Reactivity Viscosity Color 76% 8.2 35 sec gel 3400cp's Clear

In the following Examples, the novolac resin contained about 6% water,based on the weight of the novolac resin. Sodium silicate, when used,contained about 4% water based on the weight of the sodium silicate.Thus, each of the following examples contained water as a blowing agent.

Example 1

A novolac-epoxy resin was formed by combining the components shown inTable 7.

TABLE 7 (1) Epoxy Resin A 100 g (2) Novolac Resin A 200 g (3) AlkylPolyamine  35 g (4) Tween 40  15 g

Components 1 and 2 were combined in a cup and then component 4 wasadded. The mixture was stirred for two minutes and then component 3 wasadded and mixed for 40 seconds. The mixture was allowed to foam.

Foam Reactivity Cream Time Foam Time Tack Free Time 15 sec 1 min, 20 sec2 min

The foam looked good. A smooth skin on surface means that cell size wassmall.

Density Open Cell Compression 32 pcF 90% >5000

Cell size 1.5-2 microns

Example 2

A novolac-epoxy resin was formed by combining the components shown inTable 8.

TABLE 8 Component Weight (g) (1) Epoxy Resin A 100 g (2) Novolac Resin A200 g (3) Alkyl Polyamine  35 g (4) Tween 40  15 g (5) GBL*  15 g *GBLis gamma butarul lactone.

Components 1, 2, 4 and 5 were combined and mixed for two minutes.Component 3 was then added and the mixture was agitated at 3000 rpm'sfor 1.5 minutes and dumped into a mold heated to 95° F.

Foam Reactivity Cream Time Foam Time Tack Free Time 15 sec 35 sec 50 sec

Exotherm was high and foam outgassed, meaning open cells were formed.Cells were small.

Example 3

A novolac-epoxy foam was formed by combining the components shown inTable 9.

TABLE 9 Component Weight (g) (1) Epoxy Resin A 100 g (2) Novolac Resin A200 g (3) Alkyl Polyamine  30 g (4) Tween 40  15 g (5) GBL  15 g

Mixed formula same as in Example 2, then dumped solution into heatedmold.

Foam Reactivity Cream Time Foam Time Tack Free Time 40 sec 50 sec 1 min,10 sec

No outgassing occurred. Foam exotherm was not as high in temperature asin Example 2. Reaction was slower and cell size was smaller, on theorder of 1 micron.

A compressive test on the foam was conducted and the results are graphedin FIGS. 1-3. The first compress is 1, the second compression 2, and thethird compression 3. As can be seen from the Figs., the paralleldirection was slightly stronger than the perpendicular and the yieldpoint occurred at a bout 70% strain.

The compressive test method was as follows. Two small blocks that wereapproximately 0.6 inch by 0.6 inch by 1 inch were cut out of the foam.One sample was oriented such that 1 inch was in the parallel directionand another such that 1 inch was in the perpendicular direction comparedto the foam rise. Each sample was placed in the compression stand andthe samples were compressed at a rate of 01 inch per minute.

Example 4

A novolac-epoxy resin was formed by combining the components shown inTable 10.

TABLE 10 Component Weight (g) (1) Epoxy Resin A 100 g (2) Novolac ResinA 200 g (3) Alkyl Polyamine  35 g (4) Tween  28 g (5) Si*  .75 g (6) GBL 15 g *Si is SF1188 (General Electric).

Components 1, 2, 4 and 6 were combined and mixed for two minutes, thencomponents 3 and 5 were added. The mixture was stirred for 35 seconds @3000 rpm's, then dumped into mold at 25° C.

Foam Reactivity Cream Time Foam Time Tack Free Time 15 sec 48 sec 1 min,40 sec

Example 5

A novolac-epoxy resin foam was formed by combining the components shownin Table 11.

TABLE 11 Component Weight (g) (1) Epoxy Resin A 150 g (2) Novolac ResinA 150 g (3) Alkyl Polyamine  25 g (4) Tween  28 g (5) Si  1 g (6) GBL 15 g

Components 1, 2, 4 and 6 were combined and mixed for two minutes, thencomponents 3 and 5 were added. The mixture was stirred at 3,000 rpm'sfor 25 seconds, and dumped into a mold.

Foam Reactivity Cream Time Foam Time Tack Free Time 35 sec 1 min, 10 sec2 min, 15 sec

Foam looked good from the skin thickness. When the foam was cut open thecells were small and friable. This foam may be suitable for someapplications.

Example 6

A novolac-epoxy resin was formed by combining the components shown inTable 12.

TABLE 12 Component Weight (g) (A) Epoxy Resin A 100 g (B) Novolac ResinA 200 g (C) Alkyl Polyamine  35 g (D) Si  1 g (E) GBL  15 g (F) Tween 28 g

Components A, B, E, and F were combined and mixed for two minutes, thencomponents C and D were added. The mixture was stirred for 35 seconds at3000 rpm's, then dumped into a mold

Foam Reactivity Cream Time Foam Time Tack Free Time 45 sec 1 min, 30 sec2 min, 38 sec

Density of Foam Cell Size of Foam 15 pcf .5-1 mm

Foam looked good. The density was high and suitable for forming panels.Skin had nice appearance with no caverns. Mixed well and no voids. Thefoam did outgas during curing, which means the presence of open cells.

Example 7

A novolac-epoxy resin foam was formed by combining the components shownin Table 13.

TABLE 13 Component Weight(g) (A) Epoxy Resin A 100 g (B) Novolac Resin A200 g (C) Alkyl Polyamine 35 g (D) Si 2.5 g (E) Tween 28 g (F) GBL 10 g

Components A, B, E, and F were combined and mixed for two minutes, thenC and D were added. The mixture was stirred at 3000 rpm's for 25seconds, and poured into a mold.

Foam Reactivity Cream Time Foam Time Tack Free Time 40 sec 1 min, 15 sec2 min, 10 sec

Density of Foam Cell Size of Foam pH 3.5 pcf .5 mm 7.2

Foam looked good and would make good insulation since the pH wasneutral. The foam had better physical than phenolic or urethane, andprovided 90% closed cells.

Compressive Flexual Tensile Strength PSI Strength PSI Strength PSIParallel to Rise 58 94 80 Perpendicular 52 105 100

Example 8

A novolac-epoxy resin was formed by combining the components shown inTable 14.

TABLE 14 Weight (g) Component (1) 200 g SLR-NPO1 (2) 100 g SLR EPO3 (3) 80 g AlO₃* (4)  5 g Tween (5)  38 g Alkylpolyamine *Flame RetardantAluminum Trihydrate

Components 1, 2, 3 and 4 were combined and mixed at 3000 rpm's for 2 to3 minutes. Then component 5 was added and mix for 35 seconds The mixturewas then poured into mold and allowed to foam.

Foam Reactivity Cream Time Foam Time Tack Free Time 32 sec 1 min, 15 sec2 min, 40 sec

Foam cells=0.5 mm

Closed cell contents=94%

ASTM F 5ol flame test “failed”. However, this foam may have suitableflame retardancy for many applications.

Example 9

A novolac-epoxy resin was formed by combining the components shown inTable 15.

TABLE 15 (1) 200 g SLR-NPO1 (2) 100 g SLR EPO3 (3) 150 g AlO₃* (4)  5 gTween (5)  38 g Alkylpolyamine

Components 1, 2, 3 and 4 were combined in a container, mixed for twominutes, then component 5 was added and mixed for 40 seconds. Themixture was then poured into a mold and allowed to foam.

Foam Reactivity Cream Time Foam Time Tack Free Time 41 sec 1 min, 31 sec2 min, 48 sec

Foam had small cells=0.5 mm

Closed cell content=92%

ASTM F 5ol flame test—flame 15 cm, smoke heavy

Still did not self-extinguish.

Example 10

A novolac-epoxy resin was formed by combining the components shown inTable 16.

TABLE 16 (1) 100 g HRJ 444 (2) 200 g SLR-NPO1 (3)  80 g Alo₃ (4)  50 gNaSi* (5)  5 g Tween (6)  38 g Alkylpolyamine

Components 1, 2, 3, 4 and 5 were combined in a container for and mixedtwo minutes, then component 6 was added mixed for 35 seconds at 3000rpm's. The mixture was then poured it into a mold and allowed to foam.

Foam Reactivity Cream Time Foam Time Tack Free Time 1 min, 2 sec 2 min,5 sec 2 min, 40 sec

Longer foam and cream time.

Closed cell count=97%

Cell size=0.5 mm

Moisture absorption<3% by volume

ASTM F 501 flame test—flame length 5 cm, self-extinguished once flamewas moved. This foam is suitable for application in mines and otherclosed-spaces where flame retardancy is desired.

Example 11

A novolac-epoxy resin was formed by combining the components shown inTable 17.

TABLE 17 Weight(g) Component (1) 200 g SLR-NPO1 (2) 100 g SLR EPO3 (3)80 g AlO₃ (4) 5 g Tween (5) 38 g Alkylpolyamine (6) 66.6 Sodium Silicate

Components 1, 2, 3, 4 and 6 were combined and mixed at 3000 rpm's for 2to 3 minutes. Then component 5 was added and mix for 35 seconds Themixture was then poured into mold and allowed to foam. A rigid foam wasformed.

An Australian Fire Test was conducted on the foam. The test procedure isdescribed as follows:

1. Principle:

A test specimen of hardened resin is positioned horizontally across a 50mm diameter hole cut in a small piece of cement sheet, and tested by theflame from a propane gas burner.

2. Apparatus and Reagents:

propane gas burner

stand for supporting the cement sheet

stopwatch

propane gas of at least 95% purity

3. Test Specimens:

the samples should be in the form of cured block of dimensions 50 mm×50mm (3 to 5 pieces)

4. Procedure:

the specimens are tested as follows:

the test block of hardened resin is positioned across the hole on thecement sheet

the propane burner is lit and the flame adjusted to melt a piece ofcopper wire (diameter 0.7 mm) in 4 to 5 sec. The flame temperature ischecked by a digital thermometer and should be greater than 700° C.

the burner is positioned perpendicularly underneath the test block

the burner flame is allowed to impinge on the test block for an initialperiod of 10 sec and then withdrawn

observe any flame or glowing

observe any smoke, most particular the color

determine the persistence time of flame glow and smoke

repeat using increasing flame application times, in increments of 10 secup to a maximum of 60 sec.

repeat for all tests blocks

average the persistence time of flame glow and smoke after the removalof the burner

5. Report:

the following information shall be reported:

whether burning occurred and if extensive emphases

the color of smoke, if any

the average persistence time for flame, glow and smoke

6. Australian Requirement:

When tested in accordance with the method detailed in above, thematerial shall fail if any of the following occur:

after an exposure time of 20 sec, the mean persistence of the flame orglow is greater than 10 sec.

after an exposure time of 60 sec, the mean persistence of the flame orglow is greater than 30 sec.

Sample pieces were cut to approximately 51 mm cubed. A 50-mm diameterhole was drilled in a 3-inch thick piece of cinder block. An 11-mmdiameter burner was placed under the block and the flame was adjusteduntil the temperature at the top-center of the hole averaged about 900°C. Each piece was tested at the following intervals with the followingresults, as shown in Table 18.

TABLE 18 Burn Time Glow Time Smoke Time Smoke Color 10 0  5 Grey 20 0 20Grey 30 0 30 Black-Grey 40 0 35 Black-Grey 50 0 50 Black-Grey 60 0 60Black-Grey

Damage to the foam was minimal. The center of the bottom surface of theblock turned black, brown, and cracked in several places. These cracksare just at the very surface of the block. Some tiny pieces of foampopped off the surface of the block as it was tested. This occurredduring the 30-second and 40 second burn tests. Thus, the rigid foampassed the rigid Australian Fire Test.

Example 12

A novolac-epoxy resin was formed by combining the components shown inTable 19.

TABLE 19 Component Weight(g) (A) Epoxy Resin A 100 g (B) Novolac Resin A200 g (C) Alkyl Polyamine 35 g (D) Si 1 g (E) GBL 15 g (F) Tween 28 g(G) Sodium Silicate 66.6 g

Components A, B, E, F and G were combined and mixed for two minutes,then components C and D were added. The mixture was stirred for 35seconds at 3000 rpm's, then allowed to foam. A flexible foam was formed.The Australian Fire Test was conducted on the foam in the same manner asExample 11. The test results are shown in Table 20.

TABLE 20 Burn Time Glow Time Smoke Time Smoke Color 10 0  5 Grey 20 0 20Grey 30 0 30 Black-Grey 40 0 40 Black-Grey 50 0 50 Black-Grey 60 0 60Black-Grey

Damage to the foam was minimal. The center of the bottom surface of theblock turned black, brown, and cracked in several places. These cracksare just at the very surface of the block. Some tiny pieces of foampopped off the surface of the block as it was tested. This occurredduring the 30-second and 40 second burn tests. Thus, the flexible foampassed the rigid Australian Fire Test.

Example 13

A lighter density novolac-epoxy resin was formed by combining thecomponents shown in Table 20.

TABLE 20 Weight(g) Component (1) 200 g SLR-NPO1 (2) 100 g HRJ 444 (3) 80g AlO₃ (4) 5 g Tween (5) 40 g Alkylpolyamine (6) 50 g Sodium Silicate(7) 1.5 g Hydrogen Active Silicone EF-10

Components 1, 2, 3, 4, 6 and 7 were combined and mixed at 3000 rpm's for30 seconds. Then component 5 was added and mix for 35 seconds Themixture was then poured into mold and allowed to foam. A flexible foamwas formed. The foam was much lighter than those formed in Examples1-12, and the density was about 4 pounds per square foot.

Example 14

A lighter density novolac-epoxy resin was formed by combining thecomponents shown in Table 21.

TABLE 21 Weight(g) Component (1) 150 g SLR-NPO1 (2) 150 g HRJ 444 (3) 40g AlO₃ (4) 5 g Tween (5) 45 g Alkylpolyamine (6) 40 g Sodium Silicate(7) 1.5 g Hydrogen Active Silicone EF-10

Components 1, 2, 3, 4, 6 and 7 were combined and mixed at 3000 rpm's for30 seconds. Then component 5 was added and mix for 35 seconds Themixture was then poured into mold and allowed to foam. A rigid foam wasformed. The foam was much lighter than those formed in Examples 1-12,and the density was about 5 pounds per square foot. The foam had 94%closed-cells and passed the Australian Burn Test.

Example 15

A lighter density novolac-epoxy resin was formed by combining thecomponents shown in Table 22.

TABLE 22 Weight(g) Component (1) 150 g SLR-NPO1 (2) 150 g HRJ 444 (3) 40g AlO₃ (4) 5 g Tween (5) 45 g Alkylpolyamine (6) 45 g Sodium Silicate(7) 2.24 g Hydrogen Active Silicone EF-10

Components 1, 2, 3, 4, 6 and 7 were combined and mixed at 3000 rpm's for30 seconds. Then component 5 was added and mix for 30 seconds Themixture was then poured into mold and allowed to foam. The foam was muchlighter than those formed in Examples 1-12, and the density was about 2pounds per square foot. The foam was very rigid and had 87%closed-cells.

While the claimed invention has been described in detail and withreference to specific embodiments thereof, it will be apparent to one ofordinary skill in the art that various changes and modifications can bemade to the claimed invention without departing from the spirit andscope thereof.

What is claimed is:
 1. A novolac-epoxy resin foam having a cross-linkedpolymeric matrix formed by reacting a composition comprising: at leastone liquid novolac resin; at least one liquid epoxy resin; and at leastone reactive blowing agent which generates a blowing gas by reactionduring curing of the novolac resin and epoxy resin and provides heat ofreaction to increase a cure speed, wherein the composition is formulatedsuch that when the novolac resin and epoxy resin are combined duringfoaming no external heat beyond ambient temperature is required toinitiate the formation of the foam and once foaming is initiated heatfrom the reactive blowing agent increases the cure speed.
 2. A foamaccording to claim 1, wherein at least 80% of the cells are closed.
 3. Afoam according to claim 1, wherein at least 90% of the cells are closed.4. A foam according to claim 1, wherein the foam is a rigidnovolac-epoxy resin foam formulated from more epoxy resin than novolacresin.
 5. A foam according to claim 1, wherein the foam is a flexiblenovolac-epoxy resin foam formulated from more novolac resin than epoxyresin.
 6. A loam according to claim 1, wherein said novolac resin ispresent in an amount of from about 5 to about 95% by weight and saidepoxy resin is present in an amount of from about 5 to about 95% byweight, all weight % based on the total weight of the composition.
 7. Afoam according to claim 1, wherein said novolac resin is present in anamount of from about 20 to about 80% by weight and said epoxy resin ispresent in an amount of from about 20 to about 80% by weight, all weight% based on the total weight of the composition.
 8. A foam according toclaim 1, wherein said novolac resin is present in an amount of fromabout 40 to about 60% by weight and said epoxy resin is present in anamount of from about 40 to about 60% by weight, all weight % based onthe total weight of the composition.
 9. A foam according to claim 1,wherein at least one novolac resin is free of epoxide groups.
 10. A foamaccording to claim 1, wherein the foam has a pH of from about 7 to about9.
 11. A foam according to claim 1, wherein the foam has a pH of about9.
 12. A foam according to claim 1, wherein the novolac resin has anumber average molecular weight of from about 100 to about 500 and theepoxy resin has a number average molecular weight of about 250 to about650.
 13. A foam according to claim 1, wherein a ratio between novolacresin and epoxy resin has been adjusted to provide a more flexible foamby increasing the amount of novolak resin.
 14. A foam according to claim1, wherein a ratio between novolac resin and epoxy resin has beenadjusted to provide a more rigid foam by increasing the amount of epoxyresin.
 15. A foam according to claim 1, wherein the foam was formedunder ambient pressure to provide a foam having a closed-cell content ofgreater than 80%.
 16. A foam according to claim 1, wherein the foam wasformed under ambient pressure to provide a foam having a closed-cellcontent of greater than 90%.
 17. A foam according to claim 1, whereinthe reactive blowing agent comprises a compound having a reactivehydrogen group and the composition further comprises an amine catalystsuch that when the reactive blowing agent and the amine catalyst arecombined hydrogen gas is formed which blows the foam and heat isproduced which increases the curing speed of the novlac and epoxyreaction.
 18. A foam according to claim 17, wherein the reactive blowingagent comprises a silicone compound having a reactive hydrogen group.19. A foam according to claim 1, wherein the reactive blowing agent ispresent in an amount such that during blowing the temperature is raisedfrom ambient temperature to about 100 to 140° F. within 1 minute aftercombining the novolac resin and epoxy resin.
 20. A foam according toclaim 1, wherein a surfactant was used to form the foam.
 21. A foamaccording to claim 20, wherein the surfactant is present in an amount offrom about 0.01% to about 5% by weight.
 22. A foam according to claim 1,wherein foam is free of hydroxyl groups to increase non-flamability. 23.A foam according to claim 1, further comprising a flame retardant toincrease non-flamability of the foam.
 24. A foam according to claim 23,wherein the flame retardant is present in a amount of from about 10% toabout 40% by weight.
 25. A foam according to claim 1, wherein the foamis a sprayed novolac-epoxy resin foam.
 26. A foam according to claim 25,wherein the composition has a viscosity of about 50 to about 1000centipoise at 25° C.
 27. A foam according to claim 25, wherein thecomposition has a viscosity of about 50 to about 500 centipoise at 25°C.
 28. A foam according to claim 25, wherein the composition has a curespeed of about 5 minutes or less.
 29. A foam according to claim 25,further comprising at least two foam layers.
 30. A foam according toclaim 29, wherein a first foam layer was sprayed on a second foam layerbefore the first foam layer cured so that the first and second foamlayers co-cured to provide adhesion between the first and second layers.31. A foam according to claim 25, wherein the sprayed foam covers anarticle.
 32. A foam according to claim 1, wherein the epoxy resin hasabout 2 or more terminal epoxide groups on average.
 33. A foam accordingto claim 1, wherein the epoxy resin has about 3 terminal epoxide groupson average.
 34. A foam according to claim 25, wherein the epoxy resinhas about 2 or more terminal epoxide groups on average.
 35. A foamaccording to claim 1, wherein the foam is an insulating foam suitablefor automotive applications in that is has high temperature resistanceand is light weight and non-toxic when burned.
 36. A foam according toclaim 1, wherein the foam is suitable for mining applications in that ishas high temperature resistance and exhibits low outgassing.
 37. A foamaccording to claim 1, wherein the foam is suitable for residential andcommercial building applications in that it is self extinguishing anddoes not produce toxic fumes when burned.
 38. A foam according to claim37, wherein the foam is in the form of a rigid support panel.
 39. A foamaccording to claim 1, wherein the foam is flexible or high strengthrigid foam suitable for airplane applications in that it has lightweight, non-toxic when burned, high temperature resistance, andcorrosion resistance.
 40. A foam according to claim 1, wherein the foamis suitable for ship applications in that it has high temperatureresistance, corrosion protection, and low toxicity when burned.
 41. Afoam according to claim 1, wherein the foam is suitable for prototypingapplications in that it has high temperature resistance and corrosionresistance.
 42. A foam according to claim 1, wherein the foam issuitable for artistic applications in that it has high temperatureresistance and corrosion resistance.
 43. A foam according to claim 1,wherein the foam is suitable for aerospace applications in that it hashigh temperature resistance and flexibility over a wide temperaturerange.
 44. A foam according to claim 1, wherein the foam is suitable forheat shielding applications in that it has high temperature resistance.45. A foam according to claim 1, wherein the foam is suitable for masstransit applications in that it has high temperature resistance and isnon-toxic.
 46. A foam according to claim 1, wherein the foam is suitablefor applications requiring high temperature resistance, non-toxicity andnon-corrosiveness.
 47. A foam according to claim 25, wherein the epoxyresin has about 3 terminal epoxide groups on average.
 48. A sprayednovolac-epoxy resin foam having a cross-linked polymeric matrix formedby spraying a foamable composition having a viscosity of about 50 toabout 1000 centipoise at 25° C. comprising: at least one liquid novolacresin having a viscosity of about 100 to about 3,000 centipoise at 25°C; at least one liquid epoxy resin having a viscosity of about 100 toabout 10,000 centipoise at 25° C.; and at least one reactive blowingagent which generates a blowing gas by reaction during curing of thenovolac resin and epoxy resin and provides heat of reaction to increasea cure speed, wherein the composition is formulated such that when thenovolac resin and epoxy resin are combined during foaming no externalheat beyond ambient temperature is required to initiate the formation ofthe foam and once foaming is initiated heat from the reactive blowingagent increases the cure speed.